
// Definition for a binary tree node.
function TreeNode(val, left, right) {
  this.val = (val===undefined ? 0 : val)
  this.left = (left===undefined ? null : left)
  this.right = (right===undefined ? null : right)
}

/**
 * @param {TreeNode} root
 * @return {number}
*/
var sumNumbers = function(root) {

};
